X-rays were discovered in 1895 by Wilhelm Röntgen. They are a form of electromagnetic radiation that can pass through soft tissue but are absorbed by dense materials like bone. X-rays are produced when high-velocity electrons collide with a metal target, releasing energy. They have properties that make them useful for medical diagnosis and treatment, as X-rays can pass through skin and organs but be absorbed by bone, allowing internal structures to be imaged.

1. X RAY

2. • X-Rays or X-radiation as a form of electromagnetic radiation.
• They are powerful waves of electromagnetic energy.
• Most of them have a wavelength ranging from 0.01 to 10
nanometers,
• corresponding to frequencies in the range 3 × 1019 Hz to
3×1016 Hz

3. DISCOVERY OF X RAY
 Discovered in 1895 by German physicist named Wilhelm
Roentgen.
 while studying cathode rays (stream of electrons) in a gas discharge
tube. He observed that another type of radiation was produced
(presumably by the interaction of electrons with the glass walls of the
tube) that could be detected outside the tube.
 This radiation could penetrate opaque substances, produce
fluorescence, blacken a photographic plate, and ionize a gas.
 He named his discovery “x rays” because “x” stands for an
unknown.

4. How Do X-Rays work?
• They are produced when high-velocity electrons collide with
the metal plates, thereby giving the energy as the X-Rays and
themselves absorbed by the metal plate.
• The X-Ray beam travels through the air and comes in contact
with the body tissues, and produces an image on a metal film.
• Soft tissue like organs and skin, cannot absorb the high-
energy rays, and the beam passes through them.
• Dense materials inside our bodies, like bones, absorb the
radiation.

6. PROPERTIES OF X-RAY
 X-rays are invisible.
 X-rays have no mass.
 X-rays travel at the speed of light in a vacuum
 X-rays travel in straight lines.
 They have a very short wavelength
 They are unaffected by electric and magnetic fields
 They cannot be refracted
 They cause ionisation (adding or removing electrons in atoms
and molecules)

7.  They are transmitted by (pass through) healthy body tissue
 They affect photographic film in the same way as visible
light (turning it black)
 They are absorbed (stopped) by metal and bone
 They can cause photoelectric emission
 They are produced when a beam of high-energy electrons
strike a metal target
 These properties make X-rays very useful for medical
diagnosis and treatment.

8. X-RAY TUBE
 X ray are produced in the x-ray tube, which is located in the
x-ray tube head.
 X-ray are generated when electrons from the filament
cross the tube and interact with the target.
 The two main component of the x-ray tube are the
cathode and the anode.

9. CATHODE
 The cathode is composed of tungsten filament which is
centered in a focusing cup.
 Electron are produced by the filament and are focused on the
target of the anode where the x-ray are produced.
 The focusing cup has a negative charge ,like the
electrons and this helps direct the electrons to the target
(focuses them ,electrons can be focused-ray cannot)

10. ANODE
 The anode in the X-ray tube is composed of a tungsten
target embedded in a copper stem.
 When electrons from the filament enter the target
and generate X-rays a lot of heat is produced.
 The copper helps to take some of the heat away from the
target so that it doesn’t get too hot.

11. Production of X-rays
 X-rays are produced when rapidly moving electrons that
have been accelerated through a potential difference of
order 1 kV to 1 MV strikes a metal target.
Evacuated
glass tube
Target
Filament

12. Production of X-rays
 Electrons from a hot element are accelerated onto a target
anode.
 The source of electrons is the cathode, or negative electrode.
Electrons are stopped or decelerated by the anode, or positive
electrode. Electrons move between the cathode and the anode
because there is a potential difference in charge between the
electrodes.
 When the electrons are suddenly decelerated on impact, some of the
kinetic energy is converted into EM energy, as X-rays.
 Less than 1 % of the energy supplied is converted into X-
radiation during this process. The rest is converted into the
internal energy of the target.

14. X-Rays Uses
Since the discovery of X-radiation, they are used in various
fields and for various purposes.
Some key uses of X-Ray are
• Medical Science
• Security
• Astronomy
• Industry
• Restoration

15. • Medical Use:
They are used for medical purposes to detect the
breakage in human bones.
• Security:
They are used as a scanner to scan the luggage of
passengers in airports, rail terminals, and other places.
• Astronomy:
It is emitted by celestial objects and are studied to
understand the environment.
• Industrial Purpose:
It is widely used to detect the defects in the welds.
• Restoration:
They are used to restoring old paintings.